Cornus Species, Pacific Dogwood, Western Flowering Dogwood

This is a native tree in western Oregon. Unfortunately it is dying out due to anthracnose. People who want to grow this tree should be aw...Read Moreare of the disease and its prevention/cure. A telltale sign is browning leaves in late spring/summer.

Dogwood anthracnose is a disease of flowering and Pacific dogwood (Cornus florida and C. nuttallii). Infection of Pacific dogwood has been reported from Washington, Oregon, Idaho, and British Columbia. In the East, infections have been reported on flowering dogwood in Massachusetts, Connecticut, New York, New Jersey, Pennsylvania, and Delaware. Recently, the disease has been detected in Maryland, Virginia, West Virginia, North and South Carolina, Tennessee and Georgia.

Maintain the health of dogwoods by watering during periods of drought. Mulching trees can help to reduce watering needs as well as protect trunks from mechanical injury. Avoid overhead watering to minimize the chance for leaf infections. Improve air circulation around trees to help dry foliage and reduce infection.

Effective control is possible only if the disease is detected before extensive dieback occurs. Prune and dispose of diseased twigs and branches to reduce potential sources of inoculum and improve tree appearance. Raking up fallen leaves may be of some benefit. Remove succulent branches as they form to prevent trunk canker formation. Avoid high nitrogen fertilizers which stimulate succulent branching. Trees with poor vigor may be bolstered by applying a balanced fertilizer in early spring.

Fungicides should be used only to supplement a cultural control program. Applications of chlorothalonil, mancozeb will protect against leaf infections. Apply 3 or 4 sprays during leaf expansion in the spring, at 10-14 day intervals. If conditions are favorable for disease development later in the growing season, additional fungicide applications may be beneficial.

A native shrub in the hills of Southern Oregon.

This tree is a protected species in British Columbia. I found this out only because I have a very old one in my back yard and we have be...Read Moreen informed that we cannot cut it down. Fortunately, it is very lovely during the short blooming period this particular tree has. Unfortunately, it was not ever taken care of and was planted beside the septic tank...hmmm, I wonder if that is why it doesn't bloom for very long.